Subobjective 2.1. Identify effects of biochar and other amendments on soil carbon, nitrogen, and micronutrient budgets and water availability over time.

Subobjective 2.2. Identify the effects of agricultural byproducts and soil water content on the emissions of carbon dioxide and nitrous oxide gases from freezing and thawing soils.

1b.Approach (from AD-416):
The research for all objectives will be conducted at the ARS Northwest irrigation and soils laboratory in Kimberly, Idaho. Project objectives will be achieved through three main studies conducted at different scales to improve our understanding and management of soil nutrients. Research for Objective 1 involves a five year field study comparing soil ammonia and greenhouse gas emissions, soil nutrient cycling and crop nutrient uptake from selected fertilizer or manure treatments combined with nitrification and urease inhibitors. More detailed field and laboratory studies will be used for Objective 2.1 to identify the effects of biochar and other amendments on nutrient cycling. Research in Objective 2.2 entails a laboratory study to collect detailed information about greenhouse gas emissions from soils during freeze thaw cycles. This project will broaden scientific knowledge of nutrient cycling in the agricultural fields to which dairy manures and fertilizers are applied, determine if selected agricultural byproducts and amendments can assist in managing nutrients and reducing emissions in arid agricultural systems, and help us better understand nutrient cycling within the broader system through validated process based models. Data from this project will be provided to scientists and organizations to improve and validate nutrient cycling models, and for other related analysis (USDA and USEPA greenhouse gas inventories, the Integrated Farm System (IFSM) model, the Voluntary Reporting of Greenhouse Gases Carbon Management Evaluation Tool (COMET-VR), the Daily Century Model (DayCent), and Dairy Management Inc. life cycle analysis).

3.Progress Report:
This report documents progress for project 5368-12000-010-00D, which started in October 2012 and continues research from project 5368-12000-009-00D Develop and Improve Strategies for Management of Irrigated Agricultural Crops and Soils.

Objective 1: Study initiation was delayed until the fall of 2012 because a vital piece of equipment (gas chromatograph) was not available by the original start date.

Objective 2a: A five-year biochar field research site was established and continues to be monitored for greenhouse gas emissions and nitrogen cycling. Two laboratory incubation microcosms were also established to monitor changes in nitrogen, micronutrients and soil water quantity. A study that improves sugarbeet utilization of mineralized nitrogen from dairy manure was published and data describing the fate of soil carbon in furrow-irrigated, manure-amended soils cropped to corn was summarized.

Objective 2b: Preliminary investigations were conducted to measure changes in aggregate stability and soil gas emissions as frozen soil thaws. Freeze-thaw cycles caused soil water to redistribute and altered the near-surface aggregate stability of wet soil. Moreover, compared to ambient conditions, carbon dioxide emissions increased by a third and nitrous oxide emissions increased by a factor of eight, each peaking 24 to 26 hours after thawing began.

4.Accomplishments
1.
Dairy manure application can increase profitability of sugarbeet crops relative to inorganic fertilizer. Using solid dairy manure as a nutrient source for sugarbeet is problematic because sugarbeet yield and quality are sensitive to both deficiencies and excesses of soil nitrogen. ARS researchers at Kimberly, Idaho determined how nitrogen availability from a one-time manure application changed in the three years following application. Farmers can eliminate nitrogen fertilizer application to sugarbeet with appropriate attention to manure application rates, residual nitrogen and timing of sugarbeet planting after manure application, potentially increasing profits 50% by reducing fertilizer costs. This research can help producers effectively use manure with sugarbeet production and minimize nitrogen losses to the environment.

2.
Crop nutrient availability varies in years following biochar application to calcareous soils. Pyrolysis of biomass produces renewable energy and biochar, which when stored in soil can move atmospheric carbon dioxide to soil carbon. ARS researchers at Kimberly, Idaho evaluated the effects of hardwood-derived biochar on irrigated calcareous soil. Compared to untreated soil, biochar produced a consistent increase in soil carbon, but had little effect on other soil nutrients, other than causing an initial, temporary increase in the availability of soil manganese. The biochar had few effects on corn silage nutrient concentrations and silage yields until the second growing season, when it reduced nitrogen and sulfur concentrations in silage and reduced yield relative to untreated soil. This research provides important guidance to farmers growing crops on biochar-amended soils.

3.
Software simplifies processing of soil greenhouse gas emission data. Calculating soil trace gas fluxes from a series of static chamber gas concentrations is time consuming because measurements from each chamber must be analyzed separately for each monitoring event. ARS researchers at Kimberly, Idaho, developed software that automatically plots data points for decision making by the user; accounts for gas temperature effects; computes gas fluxes using linear or nonlinear approaches; and calculates cumulative fluxes for each experimental unit. The software reduces the time and labor required for greenhouse gas emission studies.